In recent years, Digital Still Camera (DSC) functions that are applied to a general digital camera and a camcorder have been applied, as an essential element, to a portable terminal, such as a smart phone, a cell phone, a Portable Multimedia Player (PMP), an Motion Picture Experts Group (MPEG) Audio Layer 3 (MP3) player, a personal navigation device, a Personal Computer (PC), a laptop PC, a tablet, and any other similar and/or suitable portable electronic device, in order to enhance user convenience.
Users may take, or capture, a photograph by using a portable terminal at anytime and anywhere. Recently, due to a rapid progress of a performance and a content storage capacity of a camera mounted to a portable terminal, users may photograph printed-matter, such as a book, papers, and a pamphlet, mainly containing texts in addition to people and scenery, and may store an image in which the corresponding printed-matter is photographed, wherein the image in which the corresponding printed-mater is photographed may be referred to as a ‘document image’, thereby utilizing the camera for preserving information recorded in the corresponding printed-matter.
According to the trend, a technology of determining whether an image that will be currently photographed is a document image and accordingly performing an appropriate and automatic adjustment for photographing conditions, including the aperture value, has been proposed. The technology is disclosed in U.S. Pat. No. 7,053,939 (Hewlett-Packard Development Company) entitled “Automatic document detection method and system” issuing to Qian Lin et al. on May 30, 2006.
In the above-mentioned related art, considering the fact that there are a comparatively large number of edge portions in a document image due to characters, an image that is input through a camera is divided into equal-sized areas, edges are detected for each of the areas, and a determination is made, for the area, as to whether the number of the edges is larger than a given threshold value, for detection of a document image. The image is determined as a document image when the total number of areas, where the number of the edges is larger than the threshold value, exceeds a specific reference value.
In the method of the related art, although a document image may be accurately judged to a certain extent, an image having a large number of edges, like an image having a complicated pattern, is more likely to be misjudged. Moreover, in a case of a document having large-sized characters, a small number of characters, or a variety of sizes or fonts, or in a case of a document having a table, such as a bus schedule, a menu table, or a calendar, the corresponding image is difficult to accurately judge as a document image.
Accordingly, there is a need for technologies to more accurately judge document images for various types and shapes of information-printed matter in daily use in addition to typical document images such as a book and papers.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.